Version 1.3 is very stable, and I've had near zero problems running from the SVN, however I did have problems with version 1.2 (VS2008 libraries were built incorrectly and is now fixed).
But I did notice that features are being added a rate much higher than that of SDL/Allegro, and is still faster than either, which I find impressive. However I did read that SDL is back in active development, which may be nice to see... I still use SDL and SFML, but I seem to be using SFML more and more.